Eradication of Hog cho em is the mainsk in the development of the hog industry and also the ob$ot of the vaccination program of the government.

Hog cholera has keen efficiently oontrolled since employir*g the bpinii hog cholera vaccine, in 1954 in Taiwan. Recently in Taiwan, in order to develop the hog industry, Large model hog farms have been estubhshed. Vaccination against hog cholera became the most important duty of the government It was known that the ooiostal antibodies of piglets were transferred by their mothers. The factors which induced the boaster antibodies of pie and poet pregnant sows is still an undetermined qnestion that the authors hore to understond. 21 heads of sows from TSC Nang-Ching hlingfarrnwereuserlinthesturlies. Ailsows wexevaccinatecl2or3 times with Lapini2ed HC vaccine during? months. Then they were divided into 4 groups as the following: (1) Booster vaccination before pregnancy. (2) Booster vaccination at one month aft pregnancy. (3) Booster vaccination at 3 months aftr pregnancy. (4) The oontrol group which was vaccinati during7 months.

The blood samples were oolleei and tested by END method. The result axe Summary summarimil as follows:

1. It shows good result of Hog cholera neutralization antibody level, which booster vaccination with Lzpini2ed HC vaccine Wore pregnancy.

3. The titers axe not good in the Neutralization antibodies oft booster vaccination with lapin&d HC vaccine at 3 months aft pregnancy than Wore booster.

4. The acpiixed antibody titers choreased slowly at more level range when the sows were vaccinated rnore than 2 or 3 times, Theouth of this paper was repored at the spring meeting of the Taiwan Asscciation of Animal Huskndry and Veterinary Medicinein 1971.